watchdog does not work on windows. For some
reason file modification events are not
emitted.
Fixed by replacing watchdog with a thread
that polls the modification date ever 0.5s.
Also fixed a bug that the hit view was not
properly destructed.
This works on Windows, but it might not work on Linux.
Also the version number is not updated automatically.
I probably have to generate the file from a template, because
even though this is a python file you cannot add python code.